Splitting cards can make it so that the card count goes over what’s allowed for free users. Not only that, but it seems to be adding 2 more than it is supposed to in the count? Not sure why that happens, but using CTRL-Z to return to before when the card is split restores it to the proper count.
I might have filled up my card limit in the process of reproducing this bug, so I’d like to request a refresh to my card count - if possible - as well